1. Field of the Invention
This invention relates to handfed card readers. More particularly, the invention pertains to low insertion force card readers having continuous read-mode retention means.
2. The Prior Art
Demand for card readers has grown in recent years as many new applications become apparent. For example, card readers are increasingly employed as substitutes for coinactuated mechanisms in vending machines, turnstiles, and the like; access to many buildings often is controlled by card reader security systems; and many offices now use machines which can only be activated upon card reader command. As rapid as this growth has been, however, certain problems and deficiencies existing in present card readers must be overcome if progress is to be sustained.
In particular, the industry is in need of a single, economically-produced card reader which can be used in a variety of applications. Such a card reader must be rugged and capable of withstanding many duty cycles without excessive wear. As a corallary to this requirement, any proposed design must minimize contact wear to prolong the useful life of the card reader and reduce replacement expense. Further, the card reader must be convenient to operate, preferably by hand, so as to be operable by all types of users without supervision or assistance. The card reader also should have a positive card retention system since, for many applications, the read-mode must be sustained throughout the performance of the controlled device. Finally, the ideal card reader, for commercial reasons, must have a minimal number of parts, be simple in design, and be inexpensive to manufacture.
Herefore, no card reader had been achieved which could entirely satisfy the above-mentioned demands. Many card readers employ a technique whereby an encoded card is inserted beneath a reading head and contacts, in wiping fashion, the contact members therein. This wiping action not only wears the contact tips, but with time, destroys the card surface. Other card readers, the so called zero or low insertion force versions, utilize various methods for indirectly bringing the card and the reading head into proper reading orientation. One such approach is taught by U.S. Pat. No. 3,573,434, which discloses a lever-actuated spring toggle mechanism for lowering the reading head to the card. While this reader works well, it is relatively complicated to assemble and requires substantial manual force to operate. Also, by bringing the reading head to the card there is a greater likelihood of losing precision alignment between the card and the reading contacts.